


The Breeding of Stiles Stilinski

by halcyon1993



Series: The Kinky Adventures of a Wolf and His Boy [23]
Category: Teen Wolf (TV)
Genre: Age Difference, Alpha Derek Hale, Alpha/Beta/Omega Dynamics, Anal Fingering, Anal Sex, Bottom Stiles Stilinski, Breeding, Come Inflation, Dirty Talk, Established Relationship, Hairy Derek Hale, Knotting, Lactation Kink, M/M, Male Lactation, Mates Derek Hale/Stiles Stilinski, Mating Cycles/In Heat, Mpreg, Omega Stiles Stilinski, Plot What Plot/Porn Without Plot, Pregnancy Kink, Pregnant Sex, Pregnant Stiles, Riding, Rimming, Self-Lubrication, Size Difference, Top Derek Hale, Topping from the Bottom, Wet & Messy
Language: English
Status: Completed
Published: 2018-07-25
Updated: 2018-07-25
Packaged: 2019-06-16 05:39:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,602
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15430176
Author URL: https://archiveofourown.org/users/halcyon1993/pseuds/halcyon1993
Summary: After being mated to Derek for years, Stiles wakes up one morning to a sweltering heat. Flash forward eight months, his hormones are in overdrive and he is horny 24/7. It's good that the sight of his rounded belly gets his alpha going, too.





	The Breeding of Stiles Stilinski

**Author's Note:**

  * For [Vergiss_Mein_Nicht](https://archiveofourown.org/users/Vergiss_Mein_Nicht/gifts), [Ryzal](https://archiveofourown.org/users/Ryzal/gifts), [clavius](https://archiveofourown.org/users/clavius/gifts).



> This takes place 4 years after the events of another PWP of mine, [_The Omega Specialist_](https://archiveofourown.org/works/14297469). You don't have to have read that for this to make sense, but I'd recommend you check it out anyway. It's good, if I do say so myself. ;)

Stiles wakes to the blaring alarm of the clock on his mate's bedside table. He turns over with a groan and smacks Derek on his chest to get him to switch it off, still needing a couple more hours of sleep. Sometimes he really hates his mate's job as a doctor. It has its pros too, of course, but it means that Derek has to get up early most days to get things ready at the clinic, usually a whole hour before Stiles himself has to get up for his college classes. Today is even worse, because he doesn't have a class until after midday and he wants to sleep in as long as he can.

Mercifully, Derek switches the alarm off and bathes their bedroom once more in silence. "Sorry, baby," he says, kissing Stiles' temple before he leaves the bed.

"You will be…" the eighteen-year-old mumbles, smushing his face in his mate's pillow because it smells like him.

"Oh yeah?"

The omega's response is muffled by the pillow. "Yeah."

Derek snorts, and then Stiles hears him enter their en suite bathroom and switch on the shower.

His eyes closed, Stiles tries to go back to sleep to the comforting sound of Derek humming to himself as he takes care of his morning ablutions, but sleep doesn't want to return to him. He doesn't know why—he is still tired as hell, but maybe it has something to do with how hot he feels. The sheets are practically stuck to his naked torso, so he flings them back, leaving him in just his Batman boxer-briefs, and spreads his limbs out across the king-size mattress, aiming not to have any of his skin touching itself. It doesn't help, sweat still slicking him.

Why? It isn't even summer, and last night had been cold. Why is he overwhelmingly hot this morning?

He groans again and checks the time. 6:36 a.m. That's way too early for him.

"God-fucking-damnit," he gripes, reluctantly leaving the bed as well. Perhaps a cool shower will help, and the distraction of his mate's wet, soapy body can't hurt either.

"Make room, 'cause I'm coming in," he warns his mate, opening the shower stall once he is out of his underwear.

Derek turns to him and raises his eyebrows in surprise as he steps aside, the stall big enough for both of them to fit without feeling too cramped. It had been one of the best things Stiles found about Derek's house after they mated over four years ago and he came to live with him. He'll never forget that day, waiting in Derek's office for his first checkup as a newly presented omega. Back then he'd known his mate as Dr. Hale. He still does sometimes, whenever they get a bit kinky in bed.

His dad had taken the news of Stiles' sudden mating about as well as he could have expected. Derek's family was fine with it right away, but the sheriff wasn't happy with Derek mating his son basically as soon as they met, even if they were true mates. But as Stiles had predicted, there wasn't really anything he could do about it because, as true mates, their mating was all perfectly legal. It took the sheriff a few months to truly warm up to Derek, but his dad's opinion was important to Stiles, so he didn't rest until they had his approval.

He forced get-togethers every week and kept on top of all of his school work in hopes of showing his dad that Derek was good for him. The alpha's work ethic is impressive, and that definitely rubbed off on Stiles. The alpha promising explosive sex if he actually did his studying helped too, and his grades, while already good, became perfect. He was the best in most of his classes, and second in the others only because of Lydia Martin, literal genius.

They finally got the sheriff's approval just over a year into their relationship.

"You alright?" Derek asks him. "You look really red."

Stiles reaches for the knob that controls the temperature of the shower and turns it to cold. "I feel like I'm boiling to death…"

Derek's frown is deep as he steps closer and holds the back of his hand to Stiles' forehead. "Damn, you are," the thirty-three-year-old says, slipping into his professional facade. "Maybe you're getting sick or something. D'you have any other symptoms?"

"Just tired. And kinda achy," Stiles responds, staying beneath the cool water.

"Hang on; I'm going to get my thermometer. I'll be right back."

"Okay…"

Derek leaves the shower stall for a moment and rummages around in the cabinet behind the mirror above the sink, not caring that he is dripping water all over the floor. He makes a triumphant noise when he finds what he wants, but as he turns back to Stiles he stops, the thermometer clasped in his hand and an expression of suspicion on his face.

"What is it?" Stiles enquires, blinking sluggishly.

"Of course!" Derek exclaims, placing the thermometer on the edge of the sink.

"What?" Stiles repeats, more urgently now that his mate is acting so strangely.

"I need to check something to make sure, but…" Derek reenters the stall, gathers Stiles close and sticks his nose right in his neck. He has to bend down a bit to do it since, as an omega, Stiles is a whole head shorter than him. For his part, Stiles places his hands on Derek's hairy chest and just lets him do whatever he wants, trusting him completely. Omega medicine is his profession, after all, so whatever is the matter with him, Derek will figure it out in no time. Plus, having his alpha breathing against his neck feels good, sending shivers down his spine. It's when Derek growls softly against him, the vibrations making his palms tingle, that Stiles figures out what's wrong for himself. Such a sound elicits a reaction from his body that makes everything click into place.

"I'm in heat," he says, surprised.

Derek leaves his neck and nods. "You are," he confirms, his face flushed with arousal and a thin ring of red appearing around his pupils.

"But it's not due for another month," Stiles points out.

"You only came off your suppressants recently. Heats are unpredictable for a while after that."

"But mine were always like clockwork the first few months. You should know, since you helped me through them."

"It's just your body and hormones trying to readjust to their natural state."

"Shit…I have an important lecture today."

"Well there's no way you're going to make it. And I'm not going to make it into work either."

Stiles pouts for a few seconds, pissed that he'll have a bunch of work to catch up on in a week or so, but then he pushes the thoughts away. There is no use worrying about such things. For now, he has a heat to get through, something that is usually quite enjoyable for both parties. It can hurt sometimes, mainly when his body still aches to be filled in between long rounds of sweaty sex, but because Derek is always there to fill him with his perfect cock, his alpha stamina more than capable of keeping up with how needy Stiles is like this, the pain never lasts for very long.

"Come on, let's get you back to bed and I'll call work, your school and your dad," Derek says, turning off the shower.

Stiles grumbles, already feeling hot again without the cool water to help him, but he doesn't protest as Derek dries them both with a fluffy white towel and leads him back into the bedroom. He falls down atop the sheets on his mate's side of the bed, just in time for his heat to really hit him. As soon as he breathes in his alpha's scent, his stomach cramps and a fresh wave of slick practically pours from his hole, soaking into the bedding. Good thing they have a mattress protector, he muses as he closes his eyes and breathes through the pain, waiting for Derek to return.

Time seems to pass unbearably slowly, all while he continues to soak the sheets with both his slick and his sweat. When Derek finally reappears with several bottles of water and a box of energy bars in his arms, hours could have ticked by for all Stiles knows. He releases a plaintive whine as his mate wastes more time carefully placing the food and water on his bedside table instead of fucking him into the mattress like he should have been doing ages ago.

"Derek…" he whimpers, writhing atop the sheets.

"Shh, I'm here," the alpha says, dumping the last of the items in his arms and climbing back onto the bed. "What do you need?"

"You…your knot," Stiles responds, the fabric beneath him tearing as he pulls on it. "Need you to breed me."

Derek hesitates. "Are you sure?"

"That was the whole reason I stopped the suppressants, you doofus. Now get down here, fuck the living daylights out of me and fill me with your pups!"

Derek is momentarily startled by his mate's vehemence, but then he gets with the programme. He helps Stiles to turn over onto his front and grabs one of the pillows to put beneath his hips, raising his ass to the perfect height to be mounted without him having to expend precious energy keeping himself up on his knees. Once he is sure that his omega is positioned correctly, Derek pushes his thighs apart and takes his own place behind him. He cups Stiles' smooth cheeks in his hands and pulls them apart, granting himself the sight of the omega's glistening asshole.

As with every time he sees it, he thinks that he has never seen anything sexier in his whole life, and he thanks whichever Fate determined that this stunning specimen before him would be his match. He doesn't know what he did in a past life to deserve something so amazing, but he _does_ know that he will cherish every second they spend together. And that includes this heat. His alpha cock hangs heavy between his legs as he watches Stiles' hole clench repeatedly around nothing, pushing out more and more slick each time. At ten inches long and very thick, his cock is bigger than the average alpha and he knows how to use it.

But first, he has to check that Stiles is ready for him.

Derek runs his right index finger a couple of times around the omega's rim, coating it with slick. After that, he slides it inside to the last knuckle, causing Stiles to moan loudly and push back in an effort to get his finger impossibly deeper. Derek himself feels like moaning because his mate is burning-hot around him. He is always hot and wet inside, but during his heats everything is just taken to another level. He thrusts his finger in and out a couple of times before adding another, sure that every second he makes Stiles wait will be another second that he is left in pain, desperate to be filled by his alpha's cock like he demanded.

Two fingers quickly become three, and then four with Derek's pinky. It's a snug fit, but the stretch is easier than usual due to Stiles' heat.

When the omega's rim isn't quite so tight around his fingers, Derek pulls them out and can't resist leaning down and licking up some of the viscous clear fluid that has leaked copiously from Stiles' body. He starts at the eighteen-year-old's perineum and continues up to his loosened hole, dipping briefly inside before he takes his tongue back inside his mouth. His cock drips pre-come as the taste of Stiles' slick assaults his taste buds. It's slightly salty but sweet as well—like salted caramel, which just happens to be one of Derek's favourite treats.

With his hunger sated, at least for now, he uses more of Stiles' slick to lube up his cock. "Ready?"

"Been ready," Stiles grumbles, arching his back.

Derek gives a short chuckle, crawls forward and lays himself atop his mate's smaller body. The heat radiating off of him is unsurprising. He threads the fingers of their left hands together next to Stiles' head and uses his right to angle himself correctly, the uncut head of his cock poised to enter Stiles' greedy hole. With a word of warning, he begins pushing inside as easily as a knife through warm butter, Stiles' body opening up for him like it was made to do.

Once he is buried to the hilt, his pubes against the top of Stiles' cheeks and his full balls resting atop Stiles' smaller, purely decorative ones, he breathes out a sigh of relief.

"Alpha…" his omega whines, clearly wanting him to move already.

"Shh, just a moment," Derek soothes, kissing the side of his face.

"Please…hurts…"

Derek forces himself to stay still for another few seconds to get control of himself, not wanting to blow too early. It's difficult with Stiles reflexively clenching around him tight as a vice and trying to push back against his heavy weight, but he just about manages and when he isn't right on the cliff edge anymore he finally gives his impatient mate what he wants. He starts gently, arching his back so that a couple of inches leave Stiles' warmth, and then he thrusts back in slow as molasses. All the while he continues to pepper his mate with kisses, mouthing along his hot pale skin until he reaches the mating bite he'd left on the right side of Stiles' neck.

As time goes on, Derek increases the speed and force of his thrusts, until his breaths are short and he is sweating as well. It drips off of him, the skin between them like a slip 'n slide. It makes holding on to Stiles a struggle, so he gives up, raises himself up and plants his hands on either side of Stiles' head to reach a better angle. Like this, he can comfortably withdraw further from his omega's sloppy hole before slamming back in, eliciting high-pitched cries from him that are like music to his ears, only spurring him on even more.

"That what you need, baby?" he growls, balls slapping against Stiles' perineum.

Stiles' response is a shouted, "Alpha!" that echoes around the large master bedroom.

Derek can feel his knot starting to form. "Soon," he promises his mate, moving his right hand to the back of Stiles' neck to hold him in place.

It's an action that screams possessiveness, something Derek would ordinarily avoid because, even though they are true mates, he doesn't _own_ Stiles. But in the throes of passion like this, it's very easy for him to lose control of his inner alpha. It's to keep Stiles from trying to escape, as if he would ever try. Logically he is certain that right now his omega wouldn't try for anything to get away from the intense fucking Derek is giving him, not when it is all that will slake his heat, but Derek's possessive instincts don't hold stock in logic and reason. They are all-consuming, as is the instinct to breed.

Like Stiles reminded him earlier, that is the whole point of the omega even having a heat now: so that Derek can knock him up. And Derek is going to knock him up good, until his belly is round and fit to burst with all the come he is going to pump inside him. And then his belly will get round for real as their first child grows inside it. Just the thought of it is enough to return Derek to the edge of his orgasm, his knot throbbing as it begins to swell at the base of his cock.

He holds Stiles' neck tight when he whimpers, obviously able to feel that it's tougher for Derek to keep thrusting into him as violently as he is.

It only gets worse with each thrust, his engorging knot stretching Stiles' hole more and more until he forces it in with audible pops. Stiles whines with each one, his body jerking as much as it is able while stuck between Derek's hips and his strong hand. "Gonna knot you," Derek says huskily, staring down with heated eyes at the side of Stiles' face that isn't smushed into the bedding. "Fill you with my pups over and over again until the whole house is full of 'em. Can't wait for that, baby…can't wait to see you walking around with your belly all big, tits full with milk. Gonna look so fucking amazing like that, I just know it."

"Derek…" Stiles says plaintively.

"Here it comes!"

With one final thrust, Derek pushes his knot past the feeble resistance Stiles' hole puts up and then they are tied.

He collapses on top of his mate and howls into his neck as he comes, his heavy balls drawing up and his cock jerking wildly as he shoots jet after jet of thick alpha seed up in Stiles' guts, just like he'd imagined doing a couple of minutes ago. This is even better than the fantasy, though, especially when he feels Stiles clamp down tight around him as he experiences his own orgasm, soaking the pillow beneath him with his thin, useless seed.

As he comes down from his high but still shoots sluggishly within the clutch of Stiles' body, Derek regains the wherewithal to roll them both onto their sides so that he is no longer crushing him. This also takes Stiles off of the wet spot. He wraps his arms tightly around the omega, one around his chest and the other around his stomach, and sticks his nose in the short hairs at Stiles' nape, breathing in the ripe scent of him, like fruit ready to be eaten. Again his nostrils are filled with the sweet smell of his heat, a scent biologically designed to entice an alpha like him.

Mission accomplished, he'd say.

"You okay?" he enquires softly.

"I'm awesome…" Stiles slurs, still in the process of recovering.

Satisfied, Derek moves his left arm and places his large palm on Stiles' stomach, feeling how it is distended by his huge load.

"Think it'll take?" the omega asks, cuddling back into his embrace.

"If it doesn't, we've got six and a half more days to keep trying," Derek reminds him.

"Should be fun."

* * *

Eight months later, Stiles sits on their living room sofa dressed in a loose blue T-shirt and a pair of sweatpants. He laments how uncomfortable he feels, his belly swollen to ridiculous proportions, making him feel like he is the size of a house.

When he first began to show at three months and grew at an alarming rate, he'd felt fat and hideous. He really regretted laughing at all the pregnant women and omegas he'd seen on TV who complained of having the same thoughts. Karma's a bitch, and after another few months in which he just kept growing and growing, Stiles was convinced he was carrying twins, as would be just his luck. An ultrasound at his next checkup confirmed this theory and Derek was over the moon, while Stiles dreaded having to deliver two babies at once his first time.

It's tricky to carry around the weight of them. His joints all ache, he has to pee basically every five minutes and he is always hungry, despite how much food he packs away now. Most of it goes to the babies. He also has to take several naps a day, which would have been inconvenient as hell were he still going to his college classes every weekday. Fortunately for him, all of his teachers had been incredibly understanding about his pregnancy and, last month, he made the switch to doing everything online as much as possible. He still has to lug his belly all the way to campus every once in a while, but he can deal with the constant drowsiness now.

When month six rolled around, Derek finally asked him why he always covered up in baggy clothing and was never in the mood for sex.

Stiles, trusting his mate, told him the truth.

In return, Derek had given him an effusive declaration in which he reassured him that he found him just as sexy as that first day in the clinic. Even sexier, in fact, because seeing evidence of his pups growing tapped into the primal part of his brain, the alpha he usually keeps carefully restrained. A roll of his hips against Stiles' thigh had added credence to this claim, and their frank conversation resulted in a round of wild sex. They had to be creative with their positions, because neither of them wanted to put any pressure on Stiles' belly and risk injuring the pups, but they managed and in the end lay side by side on the bed, both covered in sweat and various bodily fluids.

Worst of all, though, is that, as he nears the home stretch, Stiles is perpetually horny and his nipples leak milk prematurely. He gave up trying to count how many T-shirts and pairs of underwear he got through in a single day because his milk and slick soaked through them. It eventually got so bad that Derek had done some research and bought him some special pads designed for omegas, which he could stuff in the back of his underwear to lessen how much laundry they had to do. Wearing them was a little humiliating at first, but Stiles doesn't mind as much anymore. It saves his slick from soaking through his underwear and stretchy jeans when he is in public.

Another bad thing about his raging libido is that Derek still has to maintain a steady income by working, and because of this he is never around during the day to fuck Stiles' annoyingly needy hole.

"Stupid money," Stiles murmurs, mindlessly flicking through some channels on TV.

This afternoon is yet another day replete with unfulfilled amorous desire. He sips water through a straw, using his ample belly to balance the glass hands-free; at least it's good for something.

For another half an hour he does this, glancing at the clock above the TV every few minutes. The minute hand mocks him with its slowness. When, finally, he hears the front door open, Stiles switches off the programme he hadn't even been paying attention to, places his glass on the coffee table and struggles to get to his feet on his own. Usually he needs someone to pull him up, but he is nothing if not determined and manages it after a few seconds of grunting. He presses a hand to his lower back and arches it to ease the ache that is permanently there these days and then walks—or waddles, more like—through to the foyer.

"Hey, how's my beautiful little omega doing today?" Derek greets as soon as he sees him, his leather jacket halfway off.

"Little?" Stiles responds, arching an eyebrow.

"You know what I mean."

With a good-natured roll of his eyes, Stiles kisses his alpha chastely on his thin lips. "I'm fine, I guess."

Derek finishes taking off his jacket and hangs it up with a frown. "You guess?"

"You're a doctor. I'm sure you can figure out what's wrong."

Derek appraises his mate for a few moments and then it clicks. "Ah," he says, his tongue swiping out across his bottom lip.

"Ah," Stiles echoes.

Unwilling to waste any more time when they could have been all over each other already, Stiles grabs Derek's arm and drags him through the house to their bedroom. He has to make a quick stop to the en suite to empty his bladder for the hundredth time that day, and then he rejoins Derek next to their king-size bed, made up with green sheets today.

Stiles is impatient as he tugs at the buttons of his alpha's red dress shirt, engaging in another kiss all the while, this one more passionate. When the first couple don't want to cooperate, Stiles rips his mouth from Derek's and tears the shirt open, sending buttons skittering across the dark hardwood floor. Derek huffs, mildly annoyed that yet another of his shirts has met this fate, but he gets over it quickly and undoes the buttons at the cuffs himself. Once he has carelessly tossed the offending garment to the floor—it doesn't matter if it gets wrinkled now—Derek works to strip Stiles' top half bare as well. It's much easier for him, because all he has to do is pull up the hem of the omega's T-shirt and then it's off, his sexy belly and slightly swollen chest on display.

For his part, Stiles is equally turned on by his alpha. Derek is just as attractive as he was the day they met. In fact, Stiles would say he is actually even more attractive now, bits of grey having begun to appear in his beard to give him a slightly older look. Maybe it's a bit kinky, but Stiles loves the fifteen-year age difference between them. The hair on Derek's head is still full and dark, but the omega bets it won't be too many years before some strands turn grey there too.

He can't wait.

Elsewhere, Derek's muscles are as impressive as ever. He turns his face away when the alpha tries to kiss him again because he is preoccupied looking his fill. Derek's chest is broad and hairy, his nipples dusky, hard and perfectly suckable. His chest hair tapers into a thin trail down the centre of his torso, runs down abs that seem carved from stone and disappears beneath the waistband of his belted black trousers. Stiles spends a few seconds delighting in running his fingers through his mate's coarse chest hair and gives him the kiss he denied him earlier.

"Still too many clothes," Derek murmurs against his lips.

Stiles concurs.

Getting out of his sweatpants is easy—just one shove and they're gone, his small omega cock slapping up against the underside of his belly.

Derek's trousers are, like his dress shirt, more difficult. Stiles doesn't want to wait for him to finish disrobing, so he does it for him, happy to have something to do with his hands. He unbuckles the alpha's belt, throws it to the floor, and unbuttons and unzips his trousers. Now they fall easily down Derek's toned, hairy legs and then he steps out of them and kicks them across the floor, leaving him in just his tight black boxer-briefs. His erection strains against the soft fabric.

"Let's get rid of these, too, hmm?" Stiles suggests seductively.

"Uh-huh," Derek agrees, letting him do this as well. His eyes, now a constant red, are glued to Stiles' torso.

The omega curls his fingers around the waistband of his alpha's underwear and peels them away from the tanned flesh of their wearer. When he pushes them down, Derek's cock springs free. It's more than ample at ten inches long, thick, uncut and surrounded by a dense thatch of dark curls, pre-come already beading at the slit. Stiles salivates at the sight of it, and even more drool pools on his tongue as he shoves Derek's underwear the rest of the way off and frees the alpha's low-hanging balls as well, large and sprinkled with fine hairs.

"I'm gonna ride the absolute shit out of you," he promises, giving Derek a stroke. He can't wrap his hand all the way around him.

"Fuck yeah," the alpha gasps, bucking into his omega's grip.

"On the bed. On your back," Stiles orders, the years spent with his mate making him confident enough to be bossy.

"Sir, yes, sir."

Derek turns, climbs atop the green sheets and crawls on his hands and knees to the head of the bed, briefly affording Stiles a view of his muscular, hairy cheeks and his tight little hole before he turns over. It's a wonderful sight, but while they both enjoy him rimming Derek every now and then, that isn't what he wants this time.

When the alpha is in position, his hands tucked behind his head to show off his hairy pits, Stiles gets on the bed too and straddles Derek's stomach, raised up on his knees. He reaches behind himself and sticks a couple of fingers into his dripping hole to coat them with his own slick, then he slathers the stuff over every inch of Derek's thick cock, getting him ready with nature's best lubricant.

His eyelids fluttering because of Stiles' touch, Derek fights to keep them open so that he can keep looking at his beautiful omega. He is certain that he won't ever tire of his heavily pregnant mate taking control like this, all pale skin, curves and the stretch marks that are just further proof of him carrying their kids. Flicking his eyes further up, Derek zeroes in on Stiles' nipples and licks his lips when he sees that they are glistening and ripe with milk. It has become quite a common occurrence as Stiles nears the end of his pregnancy, his body producing the stuff in preparation for providing their kids with sustenance. Like his belly, it's another thing that always taps into Derek's alpha instincts and drives him crazy, and this time is no different.

With Derek's cock all slick and ready, Stiles sinks down onto it without any fanfare, making both of them moan. It hurts a tiny bit at first, but because his hole is so needy for it the pain passes quickly and then he lifts himself back up. With his belly, Stiles can't ride Derek as hard as he had been able to before he was bred, but he finds a decent rhythm that satisfies both of them for the time being. He rolls his hips sinfully, leaning back on his arms with his hands atop Derek's shins to support himself and his legs spread wide on either side of Derek's torso.

He is aware of what he looks like and enjoys the undeniable lust he can see in his alpha's eyes, which does wonders for his self-esteem.

Derek just lies back and enjoys the show, allowing Stiles to take what he wants.

"God, look at you…" he says reverently, just about resisting the urge to plant his feet on the bed and fuck up into the tight heat around him.

"You're— you're one to talk," Stiles gasps out, changing angles slightly so that the head of the alpha's cock brushes against his prostate every time he sinks down on it.

"Oh yeah?"

"Yeah…you're so big, strong and hairy…such an _alpha_ ," Stiles elaborates, running his eyes once more over every inch of Derek he can see.

"And you're such an omega."

A minute later, Derek tires of not touching his mate and removes his hands from behind his head. First he fits them to the curve of Stiles' belly, the physical evidence of a previous mating just making this one all the hotter. Stiles grins at him knowingly, and Derek wants to wipe that expression off of his face. He moves his hands up to his swollen nipples and pinches them between his fingers and thumbs, delighting in how it makes Stiles throw his head back and moan like a whore.

"You're gonna be such a good mom," Derek murmurs, gaze glued to Stiles' chest. "So ripe…so full of milk. Gonna keep our pups well-fed, aren't you?"

"Uh-huh…" Stiles confirms, still bouncing on his alpha's thick cock, slick sliding down Derek's furry balls.

"But in the meantime, I'll reap the rewards."

With another twist, Derek gets what he was hoping for when he feels the first trickle of milk running through his fingers. He does this nearly every day, and it serves double duty—it stops Stiles from getting uncomfortably swollen, and it also turns Derek on more than he could ever describe to anyone. He gives Stiles' nipples another couple of harsh, expert twists and pinches, causing more milk to spill out all down Stiles' torso and his own arms, and then he releases them.

While his omega keeps riding him good, he brings his arms to his mouth and eagerly licks the milk from his skin. He closes his eyes as the first taste of it hits him. It's slightly sweet like Stiles' slick, but it's not nearly as potent in its flavour. It's like a thinner and more delicious version of run-of-the-mill cow's milk. Derek would be more than happy to drink this for the rest of his life instead, but he knows he'll have to give it up, at least for the most part, when the pups come. He doesn't mind, but it means he makes the most of it now, and because they both want a big family, he is sure that he'll be knocking his omega up several more times in the future.

There'll be plenty more of his mate's milk for him drink from those future pregnancies.

"Taste good?" Stiles asks him, even though he already knows the answer.

"Amazing," Derek responds between licks.

Stiles giggles, but the sound cuts off when Derek finishes cleaning himself up and wraps his hands around his ankles. The look that is in the alpha's eyes is a promise.

Sure enough, a few seconds later, after Stiles feels Derek rearranging himself a bit beneath him, he is nearly thrown off of his lap when the bearded man suddenly bucks up into him, his hips slapping against the flesh of his ass.

"Ah!" Stiles cries out. He is saved from toppling sideways by Derek's hold on his ankles.

"Get ready," the alpha says too late.

"You jerk!"

"You love it."

Stiles' ensuing glare is swiftly vanished when Derek resumes fucking up into his slick hole. It's all he can do to hold on and take it, his thighs quivering because Derek is unerringly precise in his aim for his prostate. It's times like these when Stiles is especially grateful to have an omega doctor as his mate, because the thirty-three-year-old knows his anatomy like the back of his hand and has no qualms about using that knowledge to make him scream. It's probably a good thing that the houses on either side of theirs are more than just a few feet away, because Stiles can get very loud in the throes of passion.

"Don't stop!" he exclaims, his breaths coming out in short pants.

"Wasn't planning on it," Derek responds, grinning savagely.

For several minutes Stiles is jostled about by Derek's powerful thrusts. This position is the only way they can have intense sex like they used to, and both of them relish it as much as they can because they know it will always end.

Stiles bites into his bottom lip when he feels the end coming now, Derek's knot beginning to form against his rim. This is where he becomes an active participant again, shoving himself down every time Derek thrusts up in order to get that wonderful ball of flesh where it belongs, locked up tight inside his body. Stiles' own cock aches where it hits the underside of his belly, until Derek takes one of his hands off of Stiles' ankle to stroke it roughly.

"Come for me, baby," the alpha says, injecting his voice with all of his alpha power.

Stiles can only comply.

He sinks down one last time on Derek's cock, and the knot popping past his rim is what sends him over the edge. He sprays Derek's hairy chest with several jets of his thin come while the alpha keeps stroking him through it, rubbing his thumb in circles over the glans to elicit full-body shudders and beautiful whining sounds from his mouth.

When Stiles' orgasm ends, he opens his eyes and realises that, despite his knot, Derek hasn't come yet.

"You know what I want," the alpha says when Stiles voices his confusion.

As slow as his brain is post-orgasm, it takes the omega a couple of seconds to realise what Derek means. When he does, he blushes.

"Go ahead," he mumbles, shifting to get more comfortable in Derek's lap as the alpha sits up.

In this position, Stiles is actually a little taller than Derek, something that his mate uses to his advantage. Stiles willingly bares his neck and allows the alpha to nuzzle into the vulnerable flesh, shuddering all over again when he feels the light scrape of fangs applying the exact amount of pressure to be just shy of breaking the skin and reopening his mating bite.

Derek travels down to his collarbones next, and then to his chest. Stiles can feel his breaths against his sensitive nipples as he spares a few seconds to take in the mild scent of his milk, and then it begins. Derek seals his lips around Stiles' right nipple and sucks, using his hands to massage around it to help stimulate the milk flow with practiced movements. It doesn't take long for him to get it going again, at which point he stops massaging, wraps his arms around the small of Stiles' back and drinks him down, all while grinding his hips against Stiles' ass, working his knot in deeper. The taste of his omega's milk is even better like this, taken directly from the source. It's warm and flavourful, and soon enough his stomach feels heavy with the stuff.

When the flow ceases, Derek switches to his mate's other nipple. As he suckles from it just like their pups will very soon, he gets closer and closer to his own orgasm. He growls softly when Stiles threads his fingers through his dark hair, scratching lightly across his scalp with short nails. It all feels so _good_ , Stiles' hands in his hair, the taste of his milk on his tongue, the sensation of Stiles clenching tight around his cock every few seconds.

With one last filthy grind, Derek see white behind his eyelids as he shoots deep up in his mate's guts, filling him with seed.

He stops suckling during his orgasm, rests his forehead against Stiles' collarbone and just breathes through it. When it ends, he lifts his head and stares up at his omega's pretty face.

"Happy now?" Stiles asks him amusedly.

"Yeah…"

"I'm glad, you silly alpha."

Stiles cups Derek's cheeks and grins when he sees how his beard and lips are shiny with milk. His Sourwolf is a messy drinker. "Come here," he says.

With the utmost affection, Stiles licks his own milk from Derek's face, cleaning him up, and then uses his tongue to push it into Derek's mouth, not wanting him to miss a drop he doesn't have to. The alpha sighs contentedly when he is done, still holding him as close as he can with Stiles' belly in the way.

"You're not falling asleep on me already, are you?" Stiles enquires, poking him.

"Maybe," Derek admits.

Stiles chuckles and shakes his head fondly. "At least lie down first."

Derek does so, falling down on his back. He tucks one hand back behind his head and grins dopily up at his omega.

"You're lucky you're so cute after you've just come," Stiles comments, stuck sitting where he is for another half an hour or so.

"Sorry, not sorry."

Huffing, Stiles settles in to wait out Derek's knot, his libido finally quenched.

For now.

**Author's Note:**

> After two shorter PWPs in a row, I'm back to give you guys a slightly longer one! Aren't you lucky? :P This was _a lot_ of fun to write and tapped into several of my kinks, so thank you to the people who requested it. It's no wonder that A/B/O is a big draw in this fandom and always gets more hits, because it's just so damn good and opens up a lot of space to get creative. I'd never written lactation kink before, and I don't read it very often because it usually comes with breasts, so this was an experience (thanks, clavius!). I still really liked it, but you'll notice that I decided not to give Stiles breasts here because they do absolutely nothing for me. I'm _super_ gay, in case none of you have noticed. XD
> 
> Once again, thank you to Vergiss_Mein_Nicht, Ryzal and clavius for requesting this. I hope it lived up to your expectations. :)
> 
> Up next I'll be filling a prompt for Aquodox, in which son!Stiles goes into daddy!Derek's bedroom early one morning and gets a case of curious hands when he pulls back the sheets and sees his daddy's naked body.
> 
> **P.S. Don't forget to subscribe to me to be notified when my future fics go live, which will all be Sterek. And please check out my past fics if you haven't already and are interested.**


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